AP BIOLOGY

Detailed explanation-1: -The Krebs cycle, by itself, does not require the presence of oxygen; this element is necessary for the last stage of aerobic cellular respiration, i.e., oxidative phosphorylation. Organic molecules endowed with energy (carbohydrates, lipids, proteins) are split in previous reactions.

Detailed explanation-2: -The Kreb’s Cycle is an aerobic process consisting of eight definite steps. In order to enter the Kreb’s Cycle pyruvate must first be converted into Acetyl-CoA by pyruvate dehydrogenase complex found in the mitochondria.

Detailed explanation-3: -Fuel for the Krebs cycle comes from lipids (fats) and carbohydrates, which both produce the molecule acetyl coenzyme-A (acetyl-CoA). This acetyl-CoA reacts in the first step of the eight step sequence of reactions that comprise the Krebs cycle, all of which occur inside mitochondria of eukaryotic cells.

Detailed explanation-4: -So, the correct answer is ‘C6H12O6’.